Revista de Biología Marina y Oceanografía Vol. 54, N°2: 194-203, 2019 DOI: https://doi.org/10.22370/rbmo.2019.54.2.1891 Article Catch composition of deep-sea resources of commercial importance in the Colombian Caribbean Composición de las capturas de los recursos de aguas profundas de importancia comercial en el Caribe colombiano Marcela Grijalba-Bendeck1, Jorge Paramo2* and Matthias Wolff3 1Programa de Biología Marina, Grupo de Investigación Dinámica y Manejo de Ecosistemas Marino-Costeros (DIMARCO), Facultad de Ciencias Naturales e Ingeniería, Universidad de Bogotá Jorge Tadeo Lozano, Carrera 2 No. 11-68, Edificio Mundo Marino, Rodadero, Santa Marta, Colombia. [email protected] 2Grupo de Investigación Ciencia y Tecnología Pesquera Tropical (CITEPT), Universidad del Magdalena, Carrera 32 No. 22-08, Avenida del Ferrocarril, Santa Marta, Colombia 3Leibniz-Zentrum Für Marine Tropenökologie (ZMT), University of Bremen, Fahrenheitstraße 6, 28359, Germany. matthias.wolff@ zmt-bremen.de *Corresponding author: [email protected] Resumen.- Recientes estudios en el Caribe colombiano describen el potencial para una nueva pesquería de crustáceos entre 200 a 550 m de profundidad. Con el fin de soportar planes de manejo apropiados para su utilización sostenible, el objetivo del presente estudio fue identificar la composición de la captura y detectar tendencias generales en la distribución batimétrica de las cuatro principales categorías biológicas (crustáceos, teleósteos, condrictios y moluscos), en relación con el estrato de profundidad. Una captura por unidad de área total de 8.759 ind. km-2 y 226 kg km-2 fue reportada y la mayor contribución fue soportada por los peces teleósteos (89 especies; 62% abundancia y 73% de biomasa total), dominando el estrato de profundidad de 200-300 m, seguido por los crustáceos (36 y 22%, respectivamente), para aguas más profundas (>500 m). Las especies más importantes fueron los pecesCoelorinchus caelorhincus (20,2 ind. km-2; 16,7 kg km-2) y los crustáceos Penaeopsis serrata (579 ind. km-2, 7% de la abundancia total) y Pleoticus robustus(12,6 kg km-2, 6% de la biomasa total). La información obtenida es parte de la línea de base requerida para describir el potencial efecto de las pesquerías de aguas profundas en el ecosistema y soportan futuras decisiones acerca del uso, manejo y conservación de los recursos de aguas profundas de esta región. Palabras clave: Aguas profundas, pesquería, crustáceos, Colombia, Caribe Abstract.- Recent studies in the Colombian Caribbean Sea describe the potential for a new deep-sea crustacean fishery between 200 a 550 m depth. In order to support appropriate management plans for their sustainable utilization, the goal of the present study was to identify the catch composition and to detect general trends in the bathymetric distribution of the main four biological categories (crustaceans, teleostean, chondrichthyes and molluscs), in relation to depth strata. A total catch per unit area of 8,759 ind. km-2 and 226 kg km-2 was reported and the major contribution was supported by teleostean fish (89 species; 62% abundance and 73% of total biomass), dominating the depth stratum 200-300 m, followed by crustaceans (36 and 22%, respectively) for deeper waters (> 500 m). Most important species were the fishCoelorinchus caelorhincus (20.2 ind. km-2; 16.7 kg km-2) and the crustaceans Penaeopsis serrata (579 ind. km-2, 7% of the total abundance) and Pleoticus robustus (12.6 kg km-2, 6% of the total biomass). The information obtained is part of a base line required to describing the potential effects of deep-sea fisheries on the ecosystem and supporting future decisions about use, management and conservation of deep resources for this region. Key words: Deep-sea, fishery, crustaceans, Colombia, Caribbean Introduction These potential fisheries have great economic importance in The by-catch is a major concern worldwide, it has been the emergent development of deep-sea fisheries particularly estimated in 7.3 million ton mean per year and most of the in Latin America (Arana et al. 2009), where crustaceans, contribution is from by-catch landings of shrimp fisheries as opposed to fishes, have a noticeable commercial interest (27%) (Kelleher 2005). By-catch and discards are the most (Wehrtmann & Echeverría 2007, Wehrtmann et al. 2012, important topics in fishery management (Paighambari & Pérez et al. 2013). However, it is well known that deep-sea Moslem 2012). Recent studies in the Colombian Caribbean resources are highly vulnerable to over-exploitation due to Sea revealed several areas of high concentration of their life-history characteristics that include long longevity, commercially important deep-sea decapod crustaceans (i.e., slow growth rate, late maturity and low fecundity (Morato Aristaeomorpha foliacea, Pleoticus robustus, Penaeopsis et al. 2006, Follesa et al. 2011). Therefore, deep sea stocks serrata, Metanephrops binghami) representing a potential are depleted more easily, and recovery will be much slower new deep fishery resource (Paramo & Saint-Paul 2012a,b,c). than for species in shallow waters (Roberts 2002). 194 Despite its importance, the deep-sea demersal fauna Materials and methods from the continental margin of the Colombian Caribbean is relatively unknown (Paramo et al. 2012). There is an Study area and sampling design increasing interest in the exploitation of deep-water (defined Experimental trawls during two surveys in November and here as >200 m; Cavanagh & Kyne 2006) resources in December of 2009 were carried in depths ranging from this area. Available studies from deeper waters of the 200 to 550 m in the Colombian Caribbean. Samples were Colombian Caribbean have focused on length-weight collected by the commercial shrimp vessel “Tee Claude” relationships for selected species (Díaz et al. 2000), using a trawl with a cod-end mesh size of 44.5 mm from technical reports for potential commercial fisheries knot to knot. The actual location of trawlable bottoms were (Álvarez-León & Rey-Carrasco 2003), species reports found using a commercial echosounder FURUNO FCV (Roa-Varón et al. 2003, Saavedra et al. 2004) and deep fish 1150 with a transducer at a frequency of 28 kHz, with at inventories (Polanco et al. 2010). least two hauls per 100 m depth stratum, on a grid of 60 Different studies demonstrated that fishing activities stations (10 sampled stations between 200-300 m depth, could cause significant changes in deep- sea ecosystems 26 between 300-400 m, 18 between 400-500 m, and 6 at (Bianchi et al. 2000, Labropoulou & Papaconstantinou depth >500 m) (Fig. 1). No samples were collected between 2005). Therefore, research about the by-catch associated to Cartagena and Magdalena River due to the irregular depth commercial species (shrimps) of the Colombian Caribbean in this zone. The effective haul duration was 30 min and Sea is crucial for describing the potential ecosystem effects the tow distance by the net was estimated by means of a of these fisheries and for supporting future decisions about GPS Garmin MAP 76CSx. Total and relative (%) number policies and strategies for management and conservation of and weight of individuals were recorded by categories of deep resources. Thus, the present study aimed to identify crustaceans (commercial and non-commercial), teleostean the catch composition and to detect general trends in the fish, chondrichthyes and molluscs. The deep-sea catch per bathymetric distribution of the main biological categories unit of area (CPUA) was standardized by km2 of sample (crustaceans, teleostean fish, chondrichthyes and molluscs), area for total abundance (ind. km-2) and biomass (kg km-2). in relation to depth strata of a potentially new deep-sea The swept area was estimated considering the spread of the resource in the Colombian Caribbean. net (11.58 m), using the vulnerability correction factor for shrimp trawls nets (0.7) (Sparre & Venema 1995) and the speed of the vessel (average 2.5 knots) (Gunderson 1993, King 2007). The catch composition by weight and number was standardized by depth strata; species regarded as pelagic and hard bottom associated were excluded from the analysis (D’Onghia et al. 2004). Figure 1. Study area in the Colombian Caribbean. Circles indicate the sampled stations / Área de estudio en el Caribe colombiano. Los círculos indican las estaciones muestreadas Vol. 54, N°2, 2019 195 Revista de Biología Marina y Oceanografía Statistical analysis crustacean, teleostean fish, chondrichthyes and molluscs, The quantitative species composition for each 100 m stratum were evaluated using Kruskal-Wallis non-parametric test intervals was analyzed. In each interval the dominant species (Gotelli & Ellison 2004, Zar 2009). in terms of both abundance and biomass were determined. Due to the substantial marketability of four deep-sea Results crustaceans (Aristaeomorpha foliacea, Pleoticus robustus, A total CPUA of 8,759 ind. km-2 and 226 kg km-2 were Penaeopsis serrata, Metanephrops binghami) make them obtained for all sampled stations. Highest abundance (ind. as a potential new economic resource in the Colombian km-2) was represented by teleostean fish from the total Caribbean (Paramo & Saint-Paul 2012a,b,c), were labeled calculated, followed by the crustaceans, chondrichthyes and as commercial crustaceans (CC). Non-commercial molluscs. Fish and crustaceans accounted for most of the crustacean species were named as NoCC and teleostean total catch in biomass (kg km-2), followed by chondrichthyes fish, chondrichthyans and molluscs, as total by-catch. and molluscs (Fig. 2). The calculated indices from the biomass and abundance trawl data were 1) the ratio of by-catch to CC, 2) the ratio Higher abundance and biomass for crustaceans were of chondrichthyans to CC, 3) the ratio of chondrichthyans obtained for > 500 m stratum. Highest fish abundances to total catch (TC), 4) the ratio of teleosteans to CC and occurred in the 200-300 m depth stratum and most of the 5) the ratio of NonCC to CC. Changes with depth in fish biomass was collected in depths > 500 m.